Endometriosis is defined as the ectopic presence of endometrial glands and stroma. Endometriotic tissue is comprised of tissue that is histologically similar yet biochemically and functionally different or is out of phase from that of the uterine endometrium. The disease is estimated to affect 2-18% of reproductive age women and upwards of 40% of women with infertility. The ectopic endometrial tissues, which are predominantly found in dependent portions of the pelvis and on the ovaries, are hormonally active and result in hemorrhagic lesions, endometriomas, fibrosis and adhesion formation. Likewise, the peritoneal inflammation and the altered immune system response that is associated with endometriosis have been implicated in infertility by altering the processes of normal folliculogenesis, ovulation, fertilization, and implantation. Thus, endometriosis often results in multiple gynecological problems, including pelvic pain, dysmenorrhea, dyspareunia, and infertility.
The most commonly accepted theories regarding the pathophysiology of endometriosis purport that it arises from retrograde menstruation leading to adhesion of endometrial tissues to the surfaces of the pelvis and lower abdomen, or coelomic metaplasia of embryonic cells at rest found in the peritoneum and lining the Müllerian ducts. Recent studies have also presented evidence that alterations in an individual's humoral or cell-mediated immunity might make some women more susceptible to developing endometriosis.
At present, the definitive diagnosis of endometriosis requires surgery because imaging techniques, such as ultrasound and MRI, have not been shown to be reliable in the diagnosis or staging of the disease. In an effort to find a less invasive method to diagnose endometriosis, and based on the fact that endometriosis induces a local, and likely also a systemic, inflammatory process, numerous studies have focused on markers of inflammation in the peritoneal fluid and/or serum of women with the disease.
Over the past two decades, there has been much research in the molecular biology of endometriosis. Yet, despite a growing number of studies devoted to the disease, no one has been successful in developing a serum-based diagnostic test for endometriosis.
Therefore, a diagnostic test using specific endometriosis-related markers could be useful in diagnosis and nonsurgical management of the disease